Prevent aggressive pip uninstallation of existing package

[speth]

Changes proposed in this pull request

• Determine whether the Python module is being re-installed to the same location. If not, add the --ignore-installed option to pip install

If applicable, fill in the issue number this pull request is fixing

Fixes #1230

If applicable, provide an example illustrating new features this pull request is introducing

Checklist

• The pull request includes a clear description of this code change
• Commit messages have short titles and reference relevant issues
• Build passes (scons build & scons test) and unit tests address code coverage
• Style & formatting of contributed code follows contributing guidelines
• The pull request is ready for review

[ischoegl]

Pre-emptively approving. @bryanwweber, please raise objections as necessary ... 😉